Method for comprehensive recovery of heavy metal from spent solder stripper

Abstract

The invention discloses a method for comprehensive recovery of a heavy metal from a spent solder stripper, which mainly comprises steps as follows: a first step: adding pure ammonia to the spent solder stripper and adjusting pH to 9-10 to cause tin and iron to generate precipitation; a second step: obtaining a filter residue and a filtrate by filtration, wherein the main component of the filtrate is a copper ammonia solution; a third step: firstly breaking the filter residue obtained in the second step into small particles, then adding a sodium hydroxide solution to the filter residue under stirring conditions, finally reacting the tin with the sodium hydroxide completely to generate sodium stannate; a fourth step: obtaining the filtrate by filtering; a fifth step: adding sodium sulfide to the filtrate under stirring conditions, then making the solution rest and precipitating the solution; a sixth step: obtaining the filtrate by filtration; a seventh step: dewatering the filtrate obtained in the sixth step to obtain the sodium stannate. The spent solder stripper with high heavy metal content, great danger, complex component and big disposal difficulty is taken as an object. The spent solder stripper can be directly employed after the tin in the spent solder stripper is recovered. The method has good economic benefits and environmental benefits.

Description

technical field [0001] The invention relates to a method for comprehensively recovering heavy metals in waste tin stripping liquid, and belongs to the technical field of wastewater treatment. Background technique [0002] The printed circuit board (PCB) industry is the foundation of modern electronics and information industries. With the development of high-tech industries, the demand for circuit boards is increasing year by year. There are as many as 20 processes in the PCB manufacturing process, in which a large amount of waste liquid including waste stripping liquid will be generated. According to each production 1000m 2 The circuit board consumes at least 0.75m 3 Calculated by tin stripping solution, the global annual consumption is 5×10 5 m 3 Tin stripping solution, the annual consumption of tin stripping solution in my country is 6×10 4 m 3 , and increases at a rapid rate. The waste tin stripping solution is the waste liquid produced by dissolving only the tin o...

AI Technical Summary

Problems solved by technology

This not only produces a large amount of waste residue, insufficient utilization of resources, difficulty in meeting discharge standards for water quality, but also high treatment costs

In recent years, distillation recovery method, acid precipitant treatment method, preparation of stannic acid products, electrolysis method and ion exchange method have appeared successively. These technical methods may produce a large amount of other waste liquid and sludge, causing secondary pollution. Moreover, the process is complicated, the conditions are strictly controlled, and the treatment cost is high, or only considering the recovery of metal tin in the tin stripping solution, the comprehensive recovery and utilization of heavy metal resources cannot be realized

Images